/**
 * Created with IntelliJ IDEA.
 * Description:
 */
import java.util.Scanner;
public class TestDemo {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        scan.close();

        //write code here......
        int ret = dig(num);
        System.out.println(ret);
    }

    public static int dig(int num){
        int count = 0;
        if(num < 0 ){
            return -1;
        }else{
            while(num  != 0  && num > 0 ){
                count++;
                num /= 10;
            }
            return count;
        }
    }
}
